1. Field of the Invention
The present invention relates to connector assemblies for securing a heat dissipation device in thermal communication with a microprocessor that is secured to a circuit substrate, such as a printed circuit board.
2. Description of the Related Art
High performance computer systems and server systems include increasingly complex, high signal speed, integrated circuit devices or microprocessors secured to printed circuit boards to accommodate efficient electronic interconnections within a small spatial footprint. These electronic interconnections are commonly made using a land grid array (LGA) that provides high density, mechanically loaded interconnects between the microprocessor and the printed circuit board. The LGA allows for reliable and efficient interconnection, test and replacement of very costly module configurations while circumventing the inherent reliability and process limitations associated with soldering of large area array packages.
The interconnection of a land grid array of a microprocessor to a printed circuit board involves a high area density of electronic contacts. These contacts must be highly reliable over a range of operating environments. Accordingly, a common method of interconnecting microprocessor to a printed circuit board utilizes a socket that is physically secured to the printed circuit board to precisely align the land grid array of the microprocessor with the land grid array of the printed circuit board, with or without an interposer. Due to the high area density of the contacts in the land grid arrays, the socket must be designed for accurate and stable positioning on the printed circuit board, as well as accurate and stable positioning of the microprocessor within the socket. In order to achieve these objectives, the dimensional tolerances of the socket are very tight.
Furthermore, variations in the mechanical load placed on the electronic contacts of the land grid array should be minimized. Such variations have been reduced by using springs to uniformly distribute the applied load and backing plates to provide support to the back side of the printed circuit board. These mechanical systems may also be responsible for the support of heat sinks in direct contact with the microprocessor to support cooling of the microprocessor during operation.
Still, the demand for precise positioning, loading, and cooling of microprocessors can be at odds with efforts to provide higher performance in less space. For example, the layout of devices on the printed circuit board must consider spatial interference between adjacent components on the board, as well other adjacent components within the same enclosure. Furthermore, increasing the number of holes in the circuit board can reduce the strength of the board and potentially interfere with circuit layout on the board. Socket designs must be efficient to avoid consuming excessive real estate on the printed circuit board and heat sinks must be designed and arranged to work efficiently without employing dimensions that would unduly enlarge the enclosure.
Therefore, there remains a need for an improved method and apparatus for securing microprocessors and heat sinks in computer systems and other consumer and industrial electronics devices. It would be desirable for such a method and apparatus to provide greater flexibility in the installation and design of the individual components, as well as the layout of the entire system.